1. Field of the Invention
This invention relates to a device for supporting a ceiling-suspended combiner which is arranged in front of an eye point of a driver within a vehicle room and in which image light of a displayed image is projected so that it is visually recognized as an virtual image from the eye point.
2. Description of the Related Art
In a xe2x80x9chead-up displayxe2x80x9d in which the displayed image of information on vehicle driving is visually recognized as a virtual image from an eye point, the image light of the displayed image is projected onto a front glass in front of the eye point or a combiner of a transparent material arranged in front of the eye point.
Where the image light of the displayed image is to be projected onto the combiner, in order that the combiner is located in a field of view in front of the eye point, as disclosed in JP-A-5-77657, the combiner is suspended from an interior ceiling in front of the eye point.
In this case, in a vehicle, generally, in order that the driver""s head does not bump against the ceiling, a suitable interval is assured therebetween. Therefore, the eye point which is at a position lower than the head is necessarily separated from the ceiling by a larger interval.
Therefore, in order to arrange the combiner suspended from the ceiling in front of the eye point, a member for suspending the combiner must have a certain length. Therefore, the vibration of the combiner or member for suspending is not negligible in order to recognize the virtual image of the displayed image visually with no movement from the eye point
An object of this invention is to provide a device for supporting a combiner for use in a vehicle display system, which permits a displayed virtual image of vehicle driving information to be visually recognized with no shaking or movement in a vehicle which is susceptible to the vibration from the road.
In order to attain the above object, in accordance with this invention, there is provided a supporting device for supporting a combiner for a vehicle display system which is suspended from a ceiling of a vehicle room and located in front of an eye point in the vehicle room and on which image light of a displayed image for driving information is projected so that a virtual image of the displayed image is visually recognized from the eye point, comprising:
a first arm with the one end pivoted on the ceiling and the other end attached to the combiner, the first arm being swingable around a pivoting point at the one end;
a second arm with the one end pivoted on the ceiling which is apart from the one end of the first arm in a horizontal direction of the vehicle; and
a third arm with the one end pivoted on the other end of the second arm and the other end pivoted on the other end of the first arm, wherein
in a developed state of the combiner where the first arm extends along a vertical line passing the center of gravity of the combiner and the combiner is arranged in front of the eye point, the second arm and the third arm are aligned on and extended along a line which couples a pivoting point at the one end of the second arm on the ceiling and an attaching point at the other end of the first arm to the combiner; and
in a folded state of the combiner where the first arm extends substantially along the ceiling and the combiner is retracted from the front of the eye point toward the ceiling, the second arm is folded relatively to the third arm from a pivoting point of the other end of the second arm on the one end of the third arm so that the second arm and the third arm are extended substantially along the ceiling.
In this configuration, the vertical shaking of the combiner is stopped by the first arm and ceiling, and the horizontal shaking thereof is stopped by the second arm, third arm and the ceiling. Thus, in the vehicle which is susceptible to the vibration from the road face, using the combiner, the displayed image of the additional information necessary for vehicle driving can be visually recognized stably with no shaking.
In a preferred embodiment of the above supporting device, the second arm and third arm are adapted so that the distance between the pivoting point where the one end of the second arm is pivoted on the ceiling and the pivoting point where the other end of the second arm is pivoted on the one end of the third arm is equal to that between the pivoting point where the one end of the third arm is pivoted on the other end of the second arm and the pivoting point where the other end of the third arm is pivoted on the other end of the first arm.
In this configuration, in order to cause the second arm and the third arm to overlap substantially completely in the folded state of the combiner, the horizontal distance to be set between the one end of the first arm and the one end of the second arm can be uniquely defined with the dimension approximately equal to the distance between both pivoting points at the one end and the other end of the first arm. This facilitates to design the supporting device easily.
In a preferred embodiment of the supporting device, it further includes a stopper means for stopping a folding movement of the other end of the second arm relative to the one end of the third arm, which is locked to at least one of the second arm and the third arm in the developed state of the combiner, the stopper means being releasable from a locked state by application of prescribed external force.
In this configuration, the horizontal movement of the combiner can be more surely stopped by the second arm, third arm and ceiling.
The above and other objects and features of the invention will be more apparent from the following description taken in conjunction with the accompanying drawings.